This section provides background information to facilitate a better understanding of the various aspects of the disclosure. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art.
Hydrocarbon fluids such as oil and natural gas are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing formation. Once a wellbore is drilled, various forms of well completion components may be installed in order to control and enhance the efficiency of producing the various fluids from the reservoir. One piece of equipment which may be installed is the swell packer. Swellable packers such as RESPACK™, SWELLPACKER®, REPACER™, DYNAFORM™, SWELLRIGHT™, FREECAP® and so forth are widely used in the oil and gas industry for many applications. For example swell packers may be used for ICD compartmentalization, multistage fracturing, gravel packing with shunt tubes, straddle assemblies, cement replacement or cement assurance.
Instead of requiring a complex setting mechanism with moving parts such as in regular cased- or open-hole packers (non-swellable), the swellable packer “setting” mechanism is that of thermodynamic absorption or osmosis of wellbore fluid, either hydrocarbons or water into the swellable elastomeric element. Specifically, swell packers generally include a sealing material that expands or swells when it comes into contact with wellbore fluids such as hydrocarbon or brine. The applications of swell packers may be limited by a number of factors including their capability of increasing in volume, their ability to create a seal, and their mechanical properties in their un-swollen and swollen states. When a swell packer is exposed to high pressure differentials downhole, the integrity of the annular seal created by a swell packer should be maintained. Since the mechanical strength of the sealing material generally decreases after expanding and swelling, the tendency of the swellable material to extrude, deform, or flow under forces from the pressure differential will be increased, resulting in a potential failure mode between the packer and the surrounding surface.
FIGS. 1a, 1b, and 1c illustrate a conventional swell packer 10 including a swellable element 12 surrounding a portion of a tubing 14 and placed within a well with the swellable element 12 exposed to the walls of the well. In this case the walls of the well are a casing 16. At both axial extremes of the swellable element 12 are gauge rings 18 that support the swellable element 12 on the tubing 14. Prior to swelling, the swell packer element is typically protected by the gage rings to avoid damages during run in hole (“RIH”). FIG. 1b shows the packer 10 after contact with a hydrocarbon or water-based wellbore fluid and the swellable element 12 has swollen to contact the casing 16 or other wellbore inner surfaces in order to develop an annular seal. The swelling pressure in the swellable element 12 can cause it to expand over the gauge rings 18. FIG. 1c illustrates the swell packer 10 subject to a differential pressure with a higher pressure in the space 20 above the packer 10 the space 22 below the packer 10, causing the swellable element 12 to extrude toward the low pressure side. The deformation in the swellable element 12 can reach severe levels and cause tearing which results in reduced performance. The extruded swellable element 12 can even segregate from the bulk of the packer components. Accordingly, the pressure sealing capability of the swell packer element is jeopardized and undermined by the extrusion. In some cases, when the extrusion is not contained, a “tunnel” may be created along the axial direction of the element causing the swell packer to fail to hold any differential pressure.